Resist fortification for magnetic media patterning

ABSTRACT

A method and apparatus for forming magnetic media substrates is provided. A patterned resist layer is formed on a substrate having a magnetically susceptible layer. A conformal protective layer is formed over the patterned resist layer to prevent degradation of the pattern during subsequent processing. The substrate is subjected to an energy treatment wherein energetic species penetrate portions of the patterned resist and conformal protective layer according to the pattern formed in the patterned resist, impacting the magnetically susceptible layer and modifying a magnetic property thereof. The patterned resist and conformal protective layers are then removed, leaving a magnetic substrate having a pattern of magnetic properties with a topography that is substantially unchanged.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.14/170,009, filed Jan. 31, 2014 (APPM/015231USD1), which is a divisionalof U.S. patent application Ser. No. 13/193,539, filed Jul. 28, 2011(APPM/015231US), now granted as U.S. Pat. No. 8,658,242, which claimsbenefit of U.S. Provisional Patent Application Ser. No. 61/368,538,filed Jul. 28, 2010 (APPM/015231USL), all of which are hereinincorporated by reference.

FIELD

Embodiments described herein relate to methods of manufacturing magneticmedia. More specifically, embodiments described herein relate topatterning of magnetic media by plasma exposure.

BACKGROUND

Magnetic media are used in various electronic devices such as hard diskdrives and magnetoresistive random access memory (MRAM) devices.Hard-disk drives are the storage medium of choice for computers andrelated devices. They are found in most desktop and laptop computers,and may also be found in a number of consumer electronic devices, suchas media recorders and players, and instruments for collecting andrecording data. Hard-disk drives are also deployed in arrays for networkstorage. MRAM devices are used in various non-volatile memory devices,such as flash drives and dynamic random access memory (DRAM) devices.

Magnetic media devices store and retrieve information using magneticfields. The disk in a hard-disk drive is configured with magneticdomains that are separately addressable by a magnetic head. The magnetichead moves into proximity with a magnetic domain and alters the magneticproperties of the domain to record information. To recover the recordedinformation, the magnetic head moves into proximity with the domain anddetects the magnetic properties of the domain. The magnetic propertiesof the domain are generally interpreted as corresponding to one of twopossible states, the “0” state and the “1” state. In this way, digitalinformation may be recorded on the magnetic medium and recoveredthereafter.

Magnetic storage media typically comprise a non-magnetic glass,composite glass/ceramic, or metal substrate with a magneticallysusceptible material between about 100 nm and about 1 μm thick depositedthereon by a deposition process, commonly a PVD or CVD process. In oneprocess, a layer comprising cobalt and platinum is sputter deposited ona structural substrate to form a magnetically active layer. Themagnetically susceptible layer is generally either deposited to form apattern, or is patterned after deposition, such that the surface of thedevice has areas of magnetic susceptibility interspersed with areas ofmagnetic inactivity denominated by orientation of their quantum spin.Where domains with different spin orientations meet, there is a regionreferred to as a Bloch wall in which the spin orientation goes through atransition from the first orientation to the second. The width of thistransition region limits the areal density of information storagebecause the Bloch wall occupies an increasing portion of the totalmagnetic domain.

To overcome the limit due to Bloch wall width in continuous magneticthin films, the domains can be physically separated by a non-magneticregion (which can be narrower than the width of a Bloch wall in acontinuous magnetic thin film). Conventional approaches to creatingdiscrete magnetic and non-magnetic areas on a medium have focused onforming single bit magnetic domains that are completely separate fromeach other, either by depositing the magnetic domains as separateislands or by removing material from a continuous magnetic film tophysically separate the magnetic domains. A patterned mask may beapplied to a non-magnetic substrate, and a magnetic material depositedover exposed portions of the non-magnetic substrate, or the magneticmaterial may be deposited before masking and patterning, and then etchedaway in exposed portions. By one method, the non-magnetic substrate istopographically patterned by etching or scribing, and the magneticallysusceptible material deposited by spin-coating or electroplating. Thedisk is then polished or planarized to expose the non-magneticboundaries around the magnetic domains. In some cases, the magneticmaterial is deposited in a patterned way to form magnetic grains or dotsseparated by a non-magnetic area.

Such methods are expected to yield storage structures capable ofsupporting data density up to about 1 TB/in², with individual domainshaving dimensions as small as 20 nm. All such methods typically resultin significant surface roughness of the medium. Altering the topographyof the substrate can become limiting because the read-write head of atypical hard-disk drive may fly as close as 2 nm from the surface of thedisk. Thus, there is a need for a process or method of patterningmagnetic media that has high resolution and does not alter thetopography of the media, and an apparatus for performing the process ormethod efficiently for high volume manufacturing.

SUMMARY

Embodiments described herein provide a method of forming a patternedmagnetic substrate by forming a patterned resist having thick portionsand thin portions on a magnetically active surface of a substrate,forming a stabilizing layer over the patterned resist, exposing portionsof the magnetically active surface to directed energy through thestabilizing layer and the thin portions of the patterned resist, andmodifying a magnetic property of the exposed portions of themagnetically active surface to form the patterned magnetic substrate.

Other embodiments provide a method of forming a patterned magneticsubstrate by forming a magnetically active layer on a structuralsubstrate, forming a pattern transfer layer on the magnetically activelayer, patterning the pattern transfer layer by a physical patterningprocess, forming a conformal protective layer over the pattern transferlayer, and modifying the magnetic properties of the magnetically activelayer according to the pattern formed in the pattern transfer layer byexposing the substrate to energy selected to penetrate portions of thepattern transfer layer.

Other embodiments include a substrate having a magnetically susceptiblelayer, the magnetically susceptible layer having a first plurality ofdomains having a magnetic property with a first value, a secondplurality of domains having a second value of the magnetic property, anda transition region between the first plurality of domains and thesecond plurality of domains, the transition region having a dimensionless than about 2 nm, wherein each of the first plurality of domains andthe second plurality of domains has a dimension less than about 25 nm.

Other embodiments include a magnetic media substrate made by forming amagnetically active layer on a structural substrate, forming a patternedresist having thick portions and thin portions in contact with themagnetically active layer, forming a conformal stabilizing layer overthe patterned resist, exposing portions of the magnetically activesurface to directed energy through the stabilizing layer and the thinportions of the patterned resist, modifying a magnetic property of theexposed portions of the magnetically active surface to form a patternedmagnetic substrate, and removing the patterned resist and thestabilizing layer.

Other embodiments provide an apparatus for processing a substrate, theapparatus having a substrate handing portion coupled to a substrateprocessing portion by one or more load-lock chambers, the substrateprocessing portion comprising a PEALD chamber and one or more plasmaimmersion chambers coupled to a transfer chamber, and the substratehandling portion comprising a loading portion, a transfer portion, andan interface portion.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 is a flow diagram summarizing a method according to oneembodiment.

FIG. 2A is a schematic side view of a device according to anotherembodiment.

FIG. 2B is a schematic side view of a device according to anotherembodiment.

FIG. 2C is a graph illustrating a magnetic property of the device ofFIG. 2B

FIG. 3 is a flow diagram summarizing a method according to anotherembodiment.

FIG. 4 is a plan view of an apparatus according to another embodiment.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation.

DETAILED DESCRIPTION

Embodiments described herein generally provide methods and apparatus forforming a patterned magnetic substrate that may be used for any purposeto which such substrates may be directed, including magnetic storage.Some embodiments form substrates for hard disk drives, while otherembodiments may form static storage devices such as MRAM devices.

FIG. 1 is a flow diagram summarizing a method 100 according to oneembodiment. The method 100 of FIG. 1 is used to form a substrate havinga pattern of magnetic properties defined according to a pattern formedin a resist layer applied to the substrate and then subsequentlyremoved. The pattern of magnetic properties results in a substrate withmagnetic domains having a dimension less than about 25 nm with verysmooth topography.

In FIG. 1, a patterned magnetic substrate is produced by forming apatterned resist layer on a substrate having a magnetically activelayer, at 102. The substrate is a structural substrate having mechanicalstrength to support the overlying layers. Substrates used are generallymetal, glass, or a carbon material such as a polymer or composite, andmay be metal alloys or composite glass substances such as glass/ceramicblends. The substrate is generally magnetically impermeable withdiamagnetic, or only very weak paramagnetic, properties. For example, insome embodiments, the magnetic susceptibility of the base layer is belowabout 10⁻⁴ (the magnetic susceptibility of aluminum is about 1.2×10⁻⁵).

The substrates are generally coated with a magnetically susceptiblematerial that provides a medium for magnetic patterning. Themagnetically susceptible material may be formed in multiple layers, eachlayer having the same or different composition. In one embodiment, afirst layer of soft magnetic material having weak magnetic properties,such as coercivity or susceptibility, is formed over the base substrate,and a second layer of hard magnetic material having stronger magneticproperties is formed over the first layer. In some embodiments, eachlayer comprises one or more elements selected from the group consistingof cobalt, platinum, nickel, molybdenum, chromium, tantalum, iron,terbium, and gadolinium. In one embodiment, the magnetically susceptiblelayer comprises a first layer of iron or iron/nickel alloy having athickness between about 100 nm and about 1,000 nm (1 μm) and a secondlayer comprising two sub-layers, each having a thickness between about30 nm and about 70 nm, such as about 50 nm, and each comprisingchromium, cobalt, and platinum. These layers may be formed by anysuitable method known to the art, such as physical vapor deposition, orsputtering, chemical vapor deposition, plasma-enhanced chemical vapordeposition, spin-coating, plating by electrochemical or electrolessmeans, and the like.

The patterned resist layer is formed by applying a resist material tothe substrate and patterning the resist layer by a physical orlithographic patterning process capable of producing features having adimension of about 50 nm or less in some embodiments, 25 nm or less insome embodiments, and 10 nm or less in some embodiments. The resistmaterial is a material that can be readily removed without affecting theunderlying magnetically susceptible material, or a material that may beleft in the finished device without adversely affecting its properties.For example, in many embodiments, the resist material is soluble in asolvent liquid, such as water or hydrocarbon. In some embodiments, theresist material is applied to the substrate as a curable liquid,patterned by physical imprint with a template, and cured by heating orUV exposure. In other embodiments, the resist material is applied to thetemplate and at least partially cured before applying the coatedtemplate to the substrate to transfer the resist material to thesubstrate. The resist material is generally also resistant todegradation by incident energy or energetic ions. In some embodiments,the resist material is a curable material, such as an epoxy orthermoplastic polymer, that will flow prior to being cured and willprovide some resistance to energetic processes after curing.

The template is generally formed from a durable material that willretain its shape through multiple cycles of imprinting a mask material.In some embodiments, the template comprises aluminum. Features formed onthe template may have dimension less than about 50 nm, such as less thanabout 25 nm, or even less than about 10 nm. In some embodiments,features having dimension between about 1 nm and about 10 nm may beformed in the template. The very small dimension features may be formedusing any process suitable for forming such small features in asubstrate. One example of such a process is electron beam writing. Ionbeam or molecular beam writing may be used in some other embodiments.

The patterned resist material defines masked and unmasked portions ofthe magnetically susceptible layer. The pattern formed in the resistmaterial generally results in portions of the magnetically susceptiblelayer covered by a thin layer of resist material, or no resist material,and other portions covered by a thick layer of resist material. Theportions covered by a thin layer, or no layer, of resist correspond tothe unmasked portions, and may be subsequently treated by exposure to aprocessing environment selected to penetrate the thin resist layerwithout penetrating the thick resist layer. In some embodiments, thethick resist layer may have a thickness between about 50 nm and about150 nm, such as between about 60 nm and about 100 nm, for example about80 nm. In some embodiments, the thin resist layer may have a thicknessbetween about 0 nm and about 20 nm, such as between about 2 nm and about10 nm, for example about 5 nm.

A suitable resist material for practicing embodiments described hereinis the Monomat resist available from Molecular Imprints, Inc., ofAustin, Tex. The Monomat resist may be used in an imprinting process asdescribed above implemented using one of the J-FIL™ imprinters, alsoavailable from Molecular Imprints, Inc.

In other embodiments, the resist material may be a photoresist materialsuch as the Advanced Patterning Film amorphous carbon resist materialapplied using a CVD process implemented on the PRODUCER® CVD systemavailable from Applied Materials, Inc., of Santa Clara, Calif.

At 104, a protective layer is formed over the patterned resist. Theprotective layer reduces or prevents damage to the resist layer, andresulting pattern degradation, during subsequent processing. Theprotective layer is generally applied in a conformal manner to preservethe pattern of thick and thin coverage regions that defines the areas tobe treated and the areas to be protected during treatment.

The protective layer, which may be a stabilization layer to stabilizethe patterned resist during processing, is a silicon containing layer insome embodiments. In one aspect, the layer may protect the thickcoverage regions of the patterned resist from excessive bombardment byenergetic species during processing. The energetic species will changethe shape and/or thickness of the thick coverage regions, changing orreducing the degree of protection afforded to the portions of themagnetically susceptible layer below the thick coverage regions, whichmay in turn degrade the pattern. In another aspect, the layer maystabilize the patterned resist during processing by providing arelatively hard boundary to contain the patterned resist layer duringprocessing, preventing migration of resist material from the thickcoverage regions to the thin coverage regions, which would also degradethe pattern.

The layer generally comprises silicon, and may comprise one or moreelements from the group consisting of oxygen, nitrogen, carbon, or anymixture thereof. The layer may comprise silicon oxide, silicon carbide,silicon nitride, silicon oxycarbide, silicon oxynitride, or SiOCN. Thelayer may also contain hydrogen in some embodiments. In otherembodiments, the protective layer may be a doped silicon layer or adoped carbon layer. For example, a silicon layer doped with carbon,oxygen, nitrogen, or a combination thereof, may be used, or a carbonlayer doped with silicon may be used.

The protective layer is generally very thin. The patterned resistfeatures openings having a dimension that defines the pattern pitch. Ina pattern having a standard feature size, the pattern pitch is thestandard feature size. The layer is usually deposited to a thicknessthat is less than ¼ the pattern pitch to preserve the openings definedby the pattern. In a pattern having different feature sizes, the layerwill be deposited to a thickness that is less than ¼ the smallestfeature size. In some embodiments, the layer has a thickness that isless than about 10 nm, such as between about 2 nm and about 5 nm or lessthan about 2 nm, for example about 1 nm or about 3 nm.

A conformal protective layer may be formed using any process adapted todeposit thin conformal films, such as conformal CVD, cyclical CVD,pulsed CVD, or ALD. In-situ plasma is typically not used, but remoteplasma may be used in some embodiments. A low temperature process ispreferred to avoid thermal damage to the patterned resist layer or themagnetically susceptible layer. The conformal protective layer isgenerally formed at a temperature less than about 150° C., such asbetween about 20° C. and about 100° C., or between about 30° C. andabout 80° C., for example about 50° C. In alternate embodiments, thelayer may be formed at an ambient temperature, for example between about10° C. and about 30° C., such as room temperature. A conformalprotective layer may be formed using a PRODUCER CVD or ALD chamber, orusing a P3I™ chamber, also available from Applied Materials, Inc.

Suitable precursors are those that may be maintained in the vapor phaseat the temperatures described above and at the low pressurescharacteristics of vapor deposition processes. Silicon containingprecursors and oxygen or nitrogen containing precursors are used to formthe conformal layer. Ozone is used as the oxygen containing precursor inmany embodiments. Ozone may be activated by heating, either remotely orin the chamber by contact with heated chamber surfaces, such as chamberwalls or gas distribution plenums. Additionally, suitable precursors aresusceptible to being activated using a remote plasma generator operatingat power levels between about 50 W and about 3,000 W. At least onesilicon precursor is used to react with oxygen or nitrogen containingspecies to deposit the protective layer. The silicon precursor may alsobe a carbon source in some embodiments. In other embodiments, a separatecarbon source may be provided. Suitable silicon source compounds for lowtemperature deposition of the type described above includebis-diethylamino silane. Chamber pressure is typically maintainedbetween about 2 Torr and about 100 Torr, and may be adjusted to controlconformality of the deposited layer.

In one exemplary atomic layer deposition process for forming a conformalprotective layer, half-reactions are performed to deposit half-layers,as is known in the ALD art. A silicon containing precursor is providedto a chamber containing the substrate to be processed to form a siliconcontaining half-layer, and then an oxygen containing precursor isprovided to complete the layer. The substrate has a magneticallysusceptible layer, and a patterned resist layer formed on themagnetically susceptible layer, as described above. Thesilicon-containing precursor is a compound or gas mixture that may bemaintained as a vapor at the processing temperatures used for thedeposition process.

For a CVD process using active oxygen species, the silicon containingprecursor may be selected from the group consisting ofoctamethylcyclotetrasiloxane (OMCTS), methyldiethoxysilane (MDEOS),bis(tertiary-butylamino)silane (BTBAS), bis(diethylamino)silane (BDEAS),tris(dimethylamino)silane (TDMAS), bis(dimethylamino)silane (BDMAS),bis(ethyl-methylamino)silane (BEMAS), tetramethyl orthosilicate (TMOS)timethylsilane (TMS) tetraethyl orthosilicate (TEOS), and combinationsthereof. In one CVD embodiment, BDEAS is a preferred silicon-containingprecursor. Gases that are optionally introduced into the chamber at thesame time as the silicon-containing precursor include carrier gases,such as helium, nitrogen, oxygen, nitrous oxide, and argon. Ozone mixedwith oxygen or active oxygen and/or nitrogen radicals generated by aremote plasma source are the preferred reactive gases. A remote plasmamay be formed by providing oxygen and/or nitrogen gas to a remote plasmagenerator and coupling RF power between about 50 W and about 3,000 W, ata frequency of 13.56 MHz and/or 350 KHz, into the generator.

For an ALD process using active oxygen or nitrogen species, the siliconcontaining precursor may be selected from the group consisting ofdichlorosilane (DCS), trichlorosilane (TCS), silicon tetrachloride,dibromosilane, silicon tetrabromide, BDEAS, OMCTS, trisilamine (TSA),silane, disilane, and combinations thereof.

The silicon containing precursor may be introduced into the chamber at aflow rate of between about 5 sccm and about 1000 sccm. An optionalcarrier gas, e.g., helium, may be introduced into the chamber at a flowrate of between about 100 sccm and about 20000 sccm. The ratio of theflow rate of the silicon containing precursor, e.g., BDEAS, to the flowrate of the carrier gas, e.g., helium, into the chamber is about 1:1 orgreater, such as between about 1:1 and about 1:100. The chamber pressuremay be greater than about 5 mTorr, such as between about 1.8 Torr andabout 100 Torr, and the temperature of a substrate support in thechamber may be between about 10° C. and about 100° C. while thesilicon-containing precursor is flowed into the chamber to deposit thelayer. More particularly, the temperature is between about 30° C. andabout 80° C. The silicon-containing precursor may be flowed into thechamber for a period of time sufficient to deposit a layer having athickness of between about 5 Å and about 200 Å. For example, thesilicon-containing precursor may be flowed into the chamber for betweenabout 0.1 seconds and about 60 seconds.

The silicon containing precursor deposits a silicon containinghalf-layer conformally on the substrate, covering the patterned resistin the masked areas and the unmasked areas, including vertical andhorizontal surfaces of the patterned resist layer. If the unmasked areasare free of resist material, for example if the magnetically susceptiblelayer is exposed in the unmasked areas, the silicon containinghalf-layer covers the magnetically susceptible layer in the unmaskedareas. The silicon containing half-layer may be a monolayer or an atomiclayer of silicon or silicon species.

A reactive oxygen containing gas, such as ozone, an ozone/oxygenmixture, oxygen radicals, and the like, is introduced into the chamberand reacts with the silicon containing half-layer to produce a conformalsilicon oxide layer. In one embodiment, a gas mixture of between about0.5% and about 10% by volume of ozone in oxygen is introduced into thechamber at a flow rate of between about 100 sccm and about 20000 sccm.The ozone/oxygen mixture may be activated by contacting with a chambersurface, such as a chamber wall, gas distributor or showerhead,controlled at a temperature between about 70° C. and about 300° C., forexample between about 100° C. and about 180° C. The chamber pressure maybe between about 5 mTorr and about 100 Torr, and the temperature of asubstrate support in the chamber may be between about 10° C. and about100° C., for example between about 30° C. and about 80° C. while theozone/oxygen gas is flowed into the chamber.

In an ALD embodiment, the silicon precursor is provided to the chamberand allowed to deposit on the surface of the substrate until alldeposition sites are consumed. Then an active oxygen or nitrogen speciesis provided to the chamber to react with the silicon precursor depositedon the substrate surface to form a conformal silicon oxide layer. Thethickness of the conformal silicon oxide layer is determined, and if ahigher thickness is desired, the process of exposure to the siliconcontaining precursor and the oxygen containing gas may be repeated untila target thickness is reached. The chamber is purged with a purge gas,substantially removing all oxygen containing species from the chamber,and the layer formation cycle repeated if desired. The conformal siliconoxide layer serves as a protective layer, which may have a thicknessbetween about 10 Å and about 200 Å, such as between about 20 Å and about50 Å. A thin conformal protective layer provides resistance againstdamage during subsequent processing while preserving the pattern formedin the resist layer.

Nitrogen and carbon precursors may also be used in a cyclical depositionprocess similar to that described above. Nitrogen source compounds suchas ammonia (NH₃) or amines (R_(x)H_(y)N, x>0, x+y=3), hydrazine (H₂N₂),substituted hydrazines (R_(x)H_(y)N₂, x>0, x+y=2), or diamines(R[NH_(x)R′_(y)]₂, x+y=3), hydrazoic acid (HN₃) or azides (RN₃), andaminosilanes (SiH_(x)R_(y)[NH_(a)R′_(b)]_(z), x+y+z=4, a+b=3) may beused to provide nitrogen. Lower hydrocarbons such as methane (CH₄),ethane (C₂H₆), propane (C₃H₅), ethylene (C₂H₄), propylene (C₃H₆), andacetylene (C₂H₂) may serve as carbon sources. In addition, variousorganosilicon compounds, for example alkylsilanes and disilanes, mayserve as carbon sources.

In some embodiments, dopants such as carbon and nitrogen may be used tocontrol the density of the conformal protective layer, which, along withthickness of the layer, controls the extent of energetic speciesimpacting the patterned resist layer during subsequent processing. Acarbon source may be included with the process gas mixture fordepositing the conformal protective layer to introduce carbon into thelayer. In some embodiments, the conformal protective layer may besubjected to a post-processing step to remove dopants such as carbonfrom the layer.

In some embodiments, adhesion of the conformal protective layer to thepatterned resist layer during plasma processing may also be enhanced byforming a transition layer comprising silicon and carbon between thepatterned resist layer and the conformal protective layer. A carbonsource may be added to the process gas mixture for a first duration,during which a silicon and carbon containing layer is deposited, andthen the carbon source may be discontinued for a second duration to forma carbon-free layer. The silicon and carbon containing layer may improveadhesion to the carbon containing resist layer by material similarity.

The foregoing operations form a patterned resist layer over themagnetically susceptible layer, and a conformal protective layer overthe patterned resist layer. The patterned resist and protective layerhave thick areas and thin areas that define regions of the magneticallysusceptible layer to be treated with energy. Regions of the magneticallysusceptible layer adjacent to thin areas of the resist and protectivelayers are treated with energy to change a magnetic property of themagnetically susceptible layer in those regions.

At 106, energy is directed toward the surface of the substrate to modifya magnetic property of the magnetically susceptible layer in theunmasked zones. The energy may be delivered as ions, as neutralparticles, or as radiation. The ions may be small ions with low atomcount, such as less than about 10 atoms each, for example molecularions, or the ions may be large ions having about 10 atoms each or more,for example macromolecular ions or cluster ions. The neutral particlesmay be neutralized species of any of the types of ions described above,or may be radical species. The radiation may be laser or electron beamradiation. The energy type and mode of delivery is generally selected topenetrate the resist and protective layer in the unmasked areas of thesubstrate while not penetrating the resist and protective layer in themasked areas. As described above, dopants may be included in theprotective layer to adjust the energy penetrating properties of theprotective layer. Depending on thickness and density of the patternedresist layer thick and thin portions and the protective layer, energeticspecies having average kinetic energy between about 100 eV and about 10keV may be used to modify a magnetic property of the substrate.

At 108, a magnetic property of selected regions of the magneticallyactive layer, as defined by the unmasked portions thereof resulting fromthe pattern of the resist layer, is modified by the directed energy. Theenergetic species penetrate into the magnetically active layer in theunmasked portions, disrupting alignment of atomic and/or molecularmagnetic moments to change magnetic coercivity, susceptibility, or othermagnetic properties in the unmasked portions. In some embodiments, themagnetically susceptible layer is demagnetized in the unmasked portions,resulting in no detectable residual magnetic field in the unmaskedportions. In other embodiments, magnetization is reduced between about50% and about 95%.

At 110, the protective layer and patterned resist layer are removed. Anyprocess that removes the layers without altering or damaging themagnetic pattern formed in the magnetically susceptible layer may beused. In one instance, a fluorine-containing plasma may be used to stripthe protective layer and the patterned resist in a single operation.Materials such as CF₄, BF₃, and SiF₄, are provided to a plasma chambercontaining the substrate, along with an oxidizing gas such as O₂, O₃,NO₃, CO, or H₂O, and a reducing gas such as H₂ or NH₃. The gases may beactivated remotely or in situ by applying dissociate energy such as RFenergy to the gases. In one embodiment, RF energy is coupled into thegas mixture using an inductive plasma source. The fluorine-containingoxidizing/reducing mixture thus generated etches the silicon-containingprotective layer and the patterned resist layer without etching themagnetically susceptible layer.

FIG. 2A is a schematic side view of a device 200 according to anotherembodiment. The device 200 is a magnetic media device at an intermediatestage of processing, and may be formed using any of the embodimentsdescribed herein. The device 200 has a magnetically susceptible layer204 formed on a structural substrate 202. The magnetically susceptiblelayer 204 and the structural substrate 202 may comprise any of thematerials or descriptions of such layers included herein. A patternedresist layer 206 having thick coverage portions 206A and thin coverageportions 206B is formed in contact with the magnetically susceptiblelayer 204. The pattern may be formed by any suitable process, includingphysical and lithographic patterning techniques, as described herein.The pattern has a pitch “d” corresponding to a minimum dimension of athick or thin coverage region of the patterned resist. A conformalprotective layer 208 is formed over the patterned resist layer 206 byprocesses described herein. The conformal protective layer 208 has athickness “t” that is no more than 25% of the pattern pitch “d”. In someembodiments, the thickness “t” of the conformal protective layer 208 isbetween about 1% and about 25% of the pattern pitch “d”, such as betweenabout 5% and about 20%, for example about 15%. The thickness “t” beingless than about 25% of the pattern pitch “d” preserves the function ofthe pattern, allowing energetic species to impact the magneticallysusceptible layer 204 in areas covered by the thin coverage portions206B and blocking the energetic species in areas covered by the thickcoverage portions 206A.

FIG. 2B is a schematic side view of a device 216 according to anotherembodiment. The device 216 is a magnetic media device that may be formedusing the processes described herein, and which may be prepared from theintermediate stage device 200 of FIG. 2A. The device 216 comprises thestructural substrate 202 as in the device 200 of FIG. 2A. A patternedmagnetically susceptible layer 210 contacts the structural substrate202, and comprises a pattern of magnetic properties. A first domain 210Aof the magnetically susceptible layer 210 has a magnetic property with afirst value, and a second domain 210B of the magnetically susceptiblelayer 210 has a second value of the magnetic property, detectablydifferent from the first value by statistically significant measurement.The first domain 210A may also be implanted with dopants such as boron,fluorine, silicon, carbon, nitrogen, oxygen, and the like, while thesecond domain 210B may be substantially free of such dopants. The firstdomain 210A may be doped with any of the aforementioned dopants to aconcentration between about 10¹⁶ and about 10²² atoms/cm³.

A contact prevention layer 212 is formed over the patterned magneticallysusceptible layer 210 to prevent the patterned magnetically susceptiblelayer 210 from contacting any operating equipment during read/writeoperations, and a lubricating layer 214 is formed over the contactprevention layer 212 to protect the read/write head from damage in theevent of contact with the device 216. The contact prevention layer istypically deposited but may be formed by a coating method in someembodiments. The contact prevention layer is generally magneticallyinactive, and may be a carbon containing layer, such as amorphouscarbon, diamond-like carbon, or carbon nitride, in some embodiments. Thelubricating layer may be a lubricious polymer, such as a fluoropolymer,and may be formed by any convenient method such as deposition orcoating.

It should be noted that the device 216 may be made by subjecting thedevice 200 of FIG. 2A to energetic species selected to penetrate thethin coverage portions 206B of the patterned resist layer 206 while notpenetrating the thick coverage portions 206A, thus changing a magneticproperty of the magnetically susceptible layer 204 covered by the thincoverage portions 206B, removing the patterned resist layer 206 and theconformal protective layer 208, and adding the contact prevention andlubrication layers 212 and 214 of FIG. 2B.

FIG. 2C is a graph illustrating a magnetic property of the magneticallysusceptible layer 210 in the device 216 of FIG. 2B. The axis 230 showsthe value of a magnetic property, for example residual magnetism ormagnetic coercivity. The axis 218 denotes a physical dimension parallelto the plane defined by the magnetically susceptible layer 210. Thevalue of the magnetic property varies from a first value 220 to a secondvalue 222 across the magnetically susceptible layer 210 according to thedomains 210A and 210B formed by the energy treatment described above inconnection with FIG. 1 or below in connection with FIG. 3. The distance224 approximately coincides with a dimension of a domain such as thedomains 210A and 210B.

The value of the magnetic property transitions from the first value 220to the second value 222, or vice versa, in a transition region “x” thatforms the interface between two magnetic domains. A detector detectingthe magnetic property in the transition region “x” would detect a valuefor the magnetic property that is different from the first value 220 andthe second value 222 by a statistically significant amount. Thedimension 226 of the transition region “x” determines the maximumstorage density of the substrate. If the dimension 226 is small,contrast between the magnetic domains is sharp and easily detected,which allows smaller domains. Because the conformal protective layer orstabilization layer formed over the patterned resist reduces patterndegradation during energy processing, devices made according toembodiments described herein may have transition regions between domainsthat have dimension less than about 2 nm, such as less than about 1 nm,for example between about 3 Å and about 8 Å.

FIG. 3 is a flow diagram summarizing a method 300 according to anotherembodiment. At 302, a pattern of susceptible and non-susceptiblelocations is formed on a magnetic substrate using a patternedsilicon-containing resist layer having a critical dimension less thanabout 50 nm, such as between about 1 nm and about 50 nm, or betweenabout 5 nm and about 15 nm, for example about 10 nm. The magneticsubstrate may be formed by depositing a magnetic layer over a structuralsubstrate, forming a patterned resist layer having thick coverageportions and thin coverage portions on the magnetic layer, and forming aconformal protective layer on the patterned resist layer using any ofthe processes described herein.

At 304 energy is directed through portions of the patternedsilicon-containing resist layer, using processes described herein, todemagnetize portions of the magnetic layer according to the patternformed in the patterned silicon-containing resist layer. The energypenetrates the patterned silicon-containing resist layer in the thincoverage portions without penetrating in the thick coverage portions,demagnetizing the areas of the magnetic layer covered by the thincoverage portions, and creating a pattern of magnetic properties in themagnetic layer. The topography of the magnetic layer is substantiallyunchanged by the patterning process.

At 306, the patterned silicon-containing resist layer is removed using aprocess that does not damage or alter the pattern of magneticproperties. The plasma process described above involving a fluorinechemistry may be used to remove the patterned silicon-containing resistlayer.

FIG. 4 is a schematic plan view of an apparatus 400 that may be used toperform embodiments described herein. The apparatus 400 comprises asubstrate handling portion 402 and a substrate processing portion 404.The substrate handling portion 402 comprises a loading station 406, atransfer station 408, and an interface station 410. Substrates areloaded into the apparatus 400 at the loading station 406. In some cases,the loading operation may comprise disposing one or more substrates on acarrier for transport through the apparatus 400. The transfer station408 moves substrates from the loading station 406 to the interfacestation 410. The transfer station 408 may comprise substrate handlingfeatures, such as flippers, if desired. The interface station 408provides substrates to an entry load-lock chamber 412 for entry to thesubstrate processing portion 404, which generally operates under vacuum.The substrate processing portion 404 comprises a plurality of substrateprocessing chambers 416 coupled to a transfer chamber 420 with atransfer robot 418 disposed therein. Each of the processing chambers 416may be a CVD chamber, an ALD chamber, a PVD chamber, a PECVD chamber, aPEALD chamber, a plasma cleaning chamber, a cool-down chamber, or aplasma immersion chamber. In one embodiment, each of the chambers 416 isa plasma immersion chamber configured to form a conformal protectivelayer over a magnetic substrate having a patterned resist layer formedthereon, subject the substrate to energy to penetrate portions of thepatterned resist and form a pattern of magnetic properties on thesubstrate, and remove the conformal protective layer and patternedresist layer, all in a single chamber. In other embodiments, functionsof the chambers 416 may be divided such that one chamber, such as aPEALD chamber, forms a conformal protective layer, another chamber, suchas a plasma immersion chamber, performs an energy treatment, and anotherchamber, such as a plasma immersion chamber, performs resist andprotective layer removal. An exit load-lock chamber 414 receivesprocessed substrates for transfer back to the substrate handling portion402.

While the foregoing is directed to embodiments of the invention, otherand further embodiments of the invention may be devised withoutdeparting from the basic scope thereof.

What is claimed is:
 1. A method of forming a magnetic media substratecomprising: forming a magnetically active layer on a structuralsubstrate; forming a patterned resist having thick portions and thinportions in contact with the magnetically active layer; forming aconformal stabilizing layer over the patterned resist; exposing portionsof the magnetically active surface to directed energy through thestabilizing layer and the thin portions of the patterned resist;modifying a magnetic property of the exposed portions of themagnetically active surface to form a patterned magnetic substrate; andremoving the patterned resist and the stabilizing layer.
 2. The methodof claim 1, wherein the forming the patterned resist comprises aphysical patterning process.
 3. The method of claim 1, wherein conformalstabilizing layer is a silicon containing layer.
 4. The method of claim2, wherein the physical patterning process is a nano-imprint process. 5.The method of claim 1, wherein exposing portions of the magneticallyactive surface to directed energy through the stabilizing layer and thethin portions comprises: generating a fluorine containing ion beam; anddirecting the fluorine containing ion beam toward the substrate, whereinthe ions have an average kinetic energy selected to penetrate the thinportions of the resist but not the thick portions of the resist.
 6. Themethod of claim 1, wherein removing the stabilizing layer and thepatterned resist comprises exposing the substrate to a fluorinecontaining gas.
 7. The method of claim 1, wherein forming a conformalstabilizing layer comprises depositing a silicon containing layer overthe patterned resist at a temperature below about 150° C.
 8. A method oftreating a magnetic media substrate comprising: forming a magneticallyactive layer on a structural substrate; forming a patterned resisthaving thick portions and thin portions in contact with the magneticallyactive layer; forming a silicon containing conformal stabilizing layerover the patterned resist; exposing portions of the magnetically activesurface to directed energy through the stabilizing layer and the thinportions of the patterned resist; and modifying a magnetic property ofthe exposed portions of the magnetically active surface to form apatterned magnetic substrate.
 9. The method of claim 8, wherein theforming the patterned resist comprises a physical patterning process.10. The method of claim 8, further comprising removing the patternedresist and the stabilizing layer.
 11. The method of claim 9, wherein thephysical patterning process is a nano-imprint process.
 12. The method ofclaim 8, wherein exposing portions of the magnetically active surface todirected energy through the stabilizing layer and the thin portionscomprises: generating a fluorine containing ion beam; and directing thefluorine containing ion beam toward the substrate, wherein the ions havean average kinetic energy selected to penetrate the thin portions of theresist but not the thick portions of the resist.
 13. The method of claim10, wherein removing the stabilizing layer and the patterned resistcomprises exposing the substrate to a fluorine containing gas.
 14. Themethod of claim 8, wherein forming a silicon containing conformalstabilizing layer comprises depositing the silicon containing conformalstabilizing layer over the patterned resist at a temperature below about150° C.
 15. The method of claim 8, wherein the silicon containingconformal stabilizing layer comprises silicon oxide, silicon carbide,silicon nitride, silicon oxycarbide, silicon oxynitride, or SiOCN.